A common approach to manage active metal salt waste from the electrochemical pyroprocessing of used nuclear fuel is to immobilize the spent electrolyte salt containing oxidized fission products into a borosilicate glass waste form. Though, borosilicate glass waste forms are known to degrade over time. One factor for degradation is the amount of chloride ions contained in active metal salt waste. Chloride ions degrade the performance, and safety, of the borosilicate glass. Therefore, there is a need for a pyroprocessing method that accounts for the significant number of chloride ions found in electrolyte salt waste from electrochemical processing that overcomes the degradation problems caused by chloride ions in long term storage of separated fission product chlorides and residual actinide chlorides from used nuclear fuel.